Carry-Over Effects and Plumage Polymorphism in Swainson's Hawks

The maintenance of genetic diversity in the face of forces such as genetic drift and natural selection has intrigued scientists for decades. Such processes should seemingly oppose diversity in a stable environment. However, environments are rarely stable in natural systems and processes can be complex. We investigate how a plumage polymorphism is maintained in a population of Swainson's Hawks (Buteo swainsoni) in northern California, USA. Swainson's Hawks are highly polymorphic in the belly, flanks and underwing coverts ranging from white to dark brown and seemingly everything in between. Generally, these morphs can be grouped into 3 general classes; light, intermediate and dark. We first examined potential fitness differences among morph classes. Specifically we examined two primary hypotheses of heterosis (i.e., heterozygote advantage) and apostatic (i.e., frequency dependant) selection. Both mechanisms have been cited before in predator populations as potential mechanisms to maintain a polymorphism. However, we found no evidence of differences in any fitness parameter between the morph classes including; nest success, nest productivity, recruitment of offspring or lifetime reproductive success. There was marginal evidence of differences in survival between morph classes with dark individuals having a slightly higher adult survival compared to intermediate and dark morph. We also examined sexual selection in this population. Individuals did not appear to mate assortatively (i.e. there was no preference for a mate based on one's own mate class). For females, there was similarly no evidence for imprinting. In contrast, males chose mates that consistently matched the maternal morph. Further, males selected mates more consistently than we expect by chance. Finally, males that were not able to select mates with the same morph class as their mother had a lower lifetime reproductive success. This result indicates that these males may not have invested as heavily in reproduction, or were lower quality males that could not attract a mate of the correct morph. This sexual selection of the males may aid in the maintenance of the polymorphism over time.We also examined carry-over effects, processes and events in one season that affect an individual or population in another. Carry-over effects are garnering greater attention in studies of migratory species. Part of this newfound interest stems from tools and techniques allowing researchers to follow individuals or glean greater insights about foraging locations in different times of the year. We used feathers as indices of body condition from both the wintering grounds in Argentina and the breeding area. Specifically, we used the average daily growth of the feather, the level of corticosterone in the feather, and number of fault bars in the retrices and remiges of breeding hawks. We used deuterium levels in feathers to determine where each feather was grown to ensure that indices of condition came from a known location. Average daily growth was correlated with mass adjusted for body size, but corticosterone in feathers and fault bars were not. For males, average daily growth of feathers grown in Argentina and number of fault bars on worn feathers were correlated with nest success demonstrating carry-over effects and that individual in good body condition on their wintering grounds had higher reproductive performance. In contrast, measures of feather condition in females were not correlated with nest success. Corticosterone in feathers was higher in breeding males, but not in females. As males are the primary providers of prey for both the female and young nestlings their condition may drive the ability of a nesting attempt to succeed because an individual in poor condition may not be able to effectively provision the female or offspring

Determination of the most appropriate method for extrapolating overall survival data from a placebo-controlled clinical trial of lenvatinib for progressive, radioiodine-refractory differentiated thyroid cancer

Background: Cost-effectiveness models for the treatment of long-term conditions often require information on survival beyond the period of available data. Objectives: This paper aims to identify a robust and reliable method for the extrapolation of overall survival (OS) in patients with radioiodine-refractory differentiated thyroid cancer receiving lenvatinib or placebo. Methods: Data from 392 patients (lenvatinib: 261, placebo: 131) from the SELECT trial are used over a 34-month period of follow-up. A previously published criterion-based approach is employed to ascertain credible estimates of OS beyond the trial data. Parametric models with and without a treatment covariate and piecewise models are used to extrapolate OS, and a holistic approach, where a series of statistical and visual tests are considered collectively, is taken in determining the most appropriate extrapolation model. Results: A piecewise model, in which the Kaplan–Meier survivor function is used over the trial period and an extrapolated tail is based on the Exponential distribution, is identified as the optimal model. Conclusion: In the absence of long-term survival estimates from clinical trials, survival estimates often need to be extrapolated from the available data. The use of a systematic method based on a priori determined selection criteria provides a transparent approach and reduces the risk of bias. The extrapolated OS estimates will be used to investigate the potential long-term benefits of lenvatinib in the treatment of radioiodine-refractory differentiated thyroid cancer patients and populate future cost-effectiveness analyses

Airborne Radar for sUAS Sense and Avoid

A primary challenge for the safe integration of small UAS operations into the National Airspace System (NAS) is traffic deconfliction, both from manned and unmanned aircraft. The UAS Traffic Management (UTM) project being conducted at the National Aeronautics and Space Administration (NASA) considers a layered approach to separation provision, ranging from segregation of operations through airspace volumes (geofences) to autonomous sense and avoid (SAA) technologies for higher risk, densely occupied airspace. Cooperative SAA systems, such as Automatic Dependent Surveillance-Broadcast (ADS-B) and/or vehicle-to-vehicle communication systems provide significant additional risk mitigation but they fail to adequately mitigate collision risks for non-cooperative (non-transponder equipped) airborne aircraft. The RAAVIN (Radar on Autonomous Aircraft to Verify ICAROUS Navigation) flight test being conducted by NASA and the Mid-Atlantic Aviation Partnership (MAAP) was designed to investigate the applicability and performance of a prototype, commercially available sUAS radar to detect and track non-cooperative airborne traffic, both manned and unmanned. The radar selected for this research was a Frequency Modulated Continuous Wave (FMCW) radar with 120 degree azimuth and 80 degree elevation field of view operating at 24.55GHz center frequency with a 200 MHz bandwidth. The radar transmits 2 watts of power thru a Metamaterial Electronically Scanning Array antenna in horizontal polarization. When the radar is transmitting, personnel must be at least 1 meter away from the active array to limit nonionizing radiation exposure. The radar physical dimensions are 18.7cm by 12.1cm by 4.1cm and it weighs less than 820 grams making it well suited for installation on small UASs. The onboard, SAA capability, known as ICAROUS, (Independent Configurable Architecture for Reliable Operations of Unmanned Systems), developed by NASA to support sUAS operations, will provide autonomous guidance using the traffic radar tracks from the onboard radar. The RAAVIN set of studies will be conducted in three phases. The first phase included outdoor, ground-based radar evaluations performed at the Virginia Techs Kentland Farm testing range in Blacksburg, VA. The test was designed to measure how well the radar could detect and track a small UAS flying in the radars field of view. The radar was used to monitor 5 test flights consisting of outbound, inbound and crossing routes at different ranges and altitudes. The UAS flown during the ground test was the Inspire 2, a quad copter weighing less than 4250 grams (10 pounds) at maximum payload. The radar was set up to scan and track targets over its full azimuthal field of view from 0 to 40 degrees in elevation. The radar was configured to eliminate tracks generated from any targets located beyond 2000 meters from the radar and moving at velocities under 1.45 meters per second. For subsequent phases of the study the radar will be integrated with a sUAS platform to evaluate its performance in flight for SAA applications ranging from sUAS to manned GA aircraft detections and tracking. Preliminary data analysis from the first outdoor ground tests showed the radar performed well at tracking the vehicle as it flew outbound and repeatedly maintained a track out to 1000 meters (maximum 1387 meters) until the vehicle slowed to a stop to reverse direction to fly inbound. As the Inspire flew inbound tracks from beyond 800 meters, a reacquisition time delay was consistently observed between when the Inspire exceeds a speed of 1.45 meters per second and when the radar indicated an inbound target was present and maintained its track. The time delay varied between 6 seconds to over 37 seconds for the inbound flights examined, and typically resulted in about a 200 meter closure distance before the Inspire track was maintained. The radar performed well at both acquiring and tracking the vehicle as it flew crossing routes out past 400 meters across the azimuthal field of view. The radar and ICAROUS software will be integrated and flown on a BFD-1400-SE8-E UAS during the next phase of the RAAVIN project. The main goal at the conclusion of this effort is to determine if this radar technology can reliably support minimum requirements for SAA applications of sUAS. In particular, the study will measure the range of vehicle detections, lateral and vertical angular errors, false and missed/late detections, and estimated distance at closest point of approach after an avoidance maneuver is executed. This last metric is directly impacted by sensor performance and indicates its suitability for the task

Statistical properties of SGR 1806-20 bursts

We present statistics of SGR 1806-20 bursts, combining 290 events detected with RXTE/PCA, 111 events detected with BATSE and 134 events detected with ICE. We find that the fluence distribution of bursts observed with each instrument are well described by power laws with indices 1.43, 1.76 and 1.67, respectively. The distribution of time intervals between successive bursts from SGR 1806-20 is described by a lognormal function with a peak at 103 s. There is no correlation between the burst intensity and either the waiting times till the next burst or the time elapsed since the previous burst. In all these statistical properties, SGR 1806-20 bursts resemble a self-organized critical system, similar to earthquakes and solar flares. Our results thus support the hypothesis that the energy source for SGR bursts is crustquakes due to the evolving, strong magnetic field of the neutron star, rather than any accretion or nuclear power.Comment: 11 pages, 4 figures, To appear in ApJ Letter

The Poisson-Boltzmann model for implicit solvation of electrolyte solutions: Quantum chemical implementation and assessment via Sechenov coefficients.

We present the theory and implementation of a Poisson-Boltzmann implicit solvation model for electrolyte solutions. This model can be combined with arbitrary electronic structure methods that provide an accurate charge density of the solute. A hierarchy of approximations for this model includes a linear approximation for weak electrostatic potentials, finite size of the mobile electrolyte ions, and a Stern-layer correction. Recasting the Poisson-Boltzmann equations into Euler-Lagrange equations then significantly simplifies the derivation of the free energy of solvation for these approximate models. The parameters of the model are either fit directly to experimental observables-e.g., the finite ion size-or optimized for agreement with experimental results. Experimental data for this optimization are available in the form of Sechenov coefficients that describe the linear dependence of the salting-out effect of solutes with respect to the electrolyte concentration. In the final part, we rationalize the qualitative disagreement of the finite ion size modification to the Poisson-Boltzmann model with experimental observations by taking into account the electrolyte concentration dependence of the Stern layer. A route toward a revised model that captures the experimental observations while including the finite ion size effects is then outlined. This implementation paves the way for the study of electrochemical and electrocatalytic processes of molecules and cluster models with accurate electronic structure methods

Prevalence of Health-Risk Behaviours Among Indigenous Australians With Diabetes: A Review

Aboriginal and Torres Strait Islander Australians are at high risk of Type 2 diabetes and its complications. Optimal lifestyle choices can improve health outcomes. A thematic review of original research publications related to smoking, nutrition, alcohol intake, physical activity and emotional wellness in Aboriginal and Torres Strait Islander Australians with diabetes was performed. Overall, 7118 English-language publications were identified by search engines (PubMed, CINAHL, Scopus, Medline-Web of Science, and Google Scholar) with search terms Indigenous Australians OR Aboriginal and Torres Strait Islanders AND diabetes AND lifestyle OR smoking OR nutrition OR alcohol OR physical activity OR emotional wellbeing and their common synonyms. After review of abstracts and publication reference lists, 36 articles met inclusion criteria and were reviewed. In general, the self-reported health-related behaviours of Aboriginal and Torres Strait Islander Australian adults with diabetes, which is predominantly Type 2 diabetes, was suboptimal. An important clinical challenge in diabetes care is to sustainably reduce smoking, improve nutrition (including alcohol use), increase physical activity, reduce sedentary time, and improve emotional wellbeing, which should lead to reduced rates of diabetes complications. Regular assessments and multi-stakeholder input, including individuals, communities, clinical, health policy, societal and government inputs and partnerships, are desirable to facilitate closing the gap in health between Aboriginal and Torres Strait Islander and non-Indigenous Australians

Paul Bishop: recalling an academic life

The rationale for this theme section of the journal on Paul Bishop, eminent physical geographer, earth scientist and researcher of human-environment relations, is explained. Paul Bishop (1949–2022), a long-time Professor of Geography at the University of Glasgow, was – indeed, still very much is – a major figure at the cutting-edge of research, scholarship, education and applications in the fields indicated. His academic work has been global in its focus – spanning four continents (Africa, Asia, Australia, and Europe), including a substantial body of inquiries centred in Scotland – and has encompassed the time-spans of planetary history (and the geotectonics of long-term landscape change), human history (and the dynamics of environmental influence on human settlement, resource use and cultural practice) and human life-spans (including the histories and heritages of locality). Paul died, too soon, early in 2022. An event to commemorate his academic life and work was held in September 2022, and several contributions to that event have now been written through in substantially revised form for the present theme section. The current piece introduces this theme section, providing a sketch of Paul’s biography, including notes on his time in Glasgow, and cross-referencing with the articles that follow. Appended is also a near-comprehensive bibliography of Paul’s published outputs